Pump constructions



Feb. 19, 1963 GONDEK 3,077,839

PUMP CONSTRUCTIQNS Filed Oct. 28, 1960 IN VENTOR Job/7 Z om/e/r ATTORNEYUnited States Patent 3,077,839 PUMP CONSTRUCTIONS John T.-Gondek, 2206Roosevelt St. NE, Minneapolis, Minn. Filed Oct. 28, 1960, Ser. No.65,665 1 Claim. (Cl. 103-126) This invention relates to an improvementin pump constructions and deals particularly with a gear type pumphaving certain advantages over the conventional type of gear pump.

Gear pumps are conventionally made with an intermediate sectionincluding intersecting arcuate chambers to accommodate the gears, andend plates secured to the ends of the intermediate section to form thechamber ends. In some instances, pumps of this type have been formedwith one end plate integral with the intermediate section. It is anobject of the present invention to provide a pump having two generallysimilar sections each of which are provided with a cavity forming a partof the pump chamber. In other words, the central section is dividedintermediate its ends, and the end sections are integral with the twocenter sections.

A feature of this construction lies in the fact that by having twosimilar pump sections which meet along a common line, the tendency forthe pump body to deflect outwardly in a radial direction is verymaterially reduced. When high pressures are being developed by the gearpump, there is a tendency for the pump body to deflect in a manner toincrease the bore size. As the body is not integrally connected to theend plates, this force is resisted by the strength of the body and themechanical connecting means securing the end plates to the body. Bydividing the pump housing intermediate the ends of the gears, the forceis resisted by the integral end walls as well as the body, thus holdingthe body from radial deflection.

A further feature of the present invention lies in the provision of ameans of relieving the pressure between the gears at a point of deadcenter between the two gears. In a gear pump, the teeth of the two gearsdo not ordinarily mesh perfectly so that there is normally a certainamount of oil which is trapped between the teeth intermediate the axesof the two gears. This point is between the inlet and the outlet of thepump. The oil which is trapped between the two gears at the point ofdead center must escape either between the teeth or past the ends of thegears or between the gears and the end walls of the pump housing. Thiscreates a frictional force between the gears which tends to increase thepower required to operate the pump. I have found that by relieving thepressure between the gear teeth at the point of dead center between thegears, two important results may be achieved. In the first place, thefrictional force caused by the trapped liquid may be eliminated. In thesecond place, if the trapped liquid is directed toward the axes of thegears, this liquid may serve as a lubricant for the gear shafts. This isparticularly advantageous when the pump is idling at high speeds and hasno head pressure to work against,

To this end, I have provided slight chamfers in the gear housingencircling the gear shafts and extending into the end walls of thehousing. A small groove is provided on a plane through the axes of thegears connecting the two chamfers. This groove is in communication withthe space between the gear teeth at their point of dead centerpermitting the pressure to escape into the chamfers, thus directinglubricant to these chamfer areas encircling the gear shafts.

A feature of this construction lies in the fact that the pump gears forma lubricating pump for the pump 3,077,830 Patented Feb. 19, 1963 minutegroove in the end walls to the chamfers, from which it may pass alongthe journals to lubricate the journals. This has resulted in an increasein the rating of the pumps very materially. Pumps of the same size whichwere previously rated at 2,000 pounds per square inch are now rated at5,000 pounds per square inch, and have been tested successfully at muchhigher pressures, due to the slight change in construction.

These .and other objects and novel features of the present inventionwill be more clearly and fully set forth in the following specificationand claim.

In the drawings forming a part of the specification:

FIGURE 1 is a sectional view through a typical form of gear pumpembodying the present invention.

FIGURE 2 is a sectional view at right angles to that of FIGURE 1, theposition of the section being indicated by the line 22 of FIGURE 1.

FIGURE 3 is a transverse sectional view through the pump illustrated inFIGURES l and 2, the position of the section being indicated by the line33 of FIG- URE 2.

FIGURE 4 is an enlarged view showing a portion of the gear teeth andshowing the manner in which fluid is trapped between the teeth of thegear.

FIGURE 5 is an enlarged sectional view showing a portion of the gearhousing .and the rotors supported therein.

The pump is indicated in general by the letter A. The pump includes ahousing which is indicated in general by the numeral 10 and whichincludes a housing section 11 and a housing section 12. The housingsections 11 and 12 are in abutting relation along a plane 13 which, inpreferred form, is intermediate the ends of the gear chambers.

As is indicated in FIGURE 3 of the drawings, the

pump housing sections 11 and 12 are provided with arcuate cavities 14and 15 which are in intersecting relation and which are designed toaccommodate the gears 16 and 17 which comprise the pump, As indicated inFIGURE 2 of the drawings, the gear 16 is provided with stub shafts 19and 20 which are supported in suitable bearings 21 and 22 in the gearpump sections 11 and 12. The gear 17 is likewise supported with axialstub shafts 23 and 24 which are supported in bearings 25 and 26 in thehousing sections 11 and 12. The stub shaft 23 projects from the housingportion 11 and is preferably encircledby an anti-friction bearing 27, asthe shaft 23 acts as the drive shaft for the pump.

As is also indicated in FIGURE 3 of the drawings, the pump section 11 isprovided with lateral passages 30 and 31 which form the pump inlet andthe pump outlet. These passages 30 and 31 are connected with inlet andoutlet openings 32 and 33 respectively which extend in a directionaxially through the pump sections. These passages 33 and 32 also extendthrough a pump base section 34 to communicate with inlet and outletsockets 35 and 36 respectively.

A series of angularly spaced bolts 37 extend through the pump housingsections 11 and 12 .and are threaded into the base section 34 to attachthe sections together. It will be noted that the chambers for containingthe gears 16 and 17 exend to either side of the center line connectingthe two pump sections so as to minimize the tendency for the extremelyhigh pressure to deflect the body in a radial direction, or in a mannerto increase the bore diameter. Radial deflection is prevented by the Asindicated in FIGURE 4 of the drawings, there is normally a tendency forliquid' to be trapped in the space '40 between 'the'too'th'4l of'6ne"'gear such as 16 and the base between the teethas indicated at 42in the other gear 17. As the gears rotate, this fluid under pressuremust es'cape'either'between'the teeth'or about the ends of the gears.The compression of this fluid causes a tendencyto stop rotation of thegears, and requires greater pressure in "orderto keep them in operation.

As is indicated in the drawings, each of the pump housing sectionsll and12 are provided with cham feis between the ends of pump housing and theends of the gears 167 A chamfer'43 encircles the stub shaft19 in thehousing section'll at'the end of the gear 17, and a similar chamfer 44is provided in the housing section 12 at the opposite end of the gear16. In a similar manner, charnfers 45'and'46a1e provided in the'housingsetions'll and'12 at opposite ends of the gear 17. These chamfers extendabout the journals 21'and 22 at their juncture with the 'gearreceivingrecesses'14 and about the journals 25 and 26 atth'eir juncture with thepuinp chambers 15. The ch'a'rnfers are very'small and terminate wellshort of the basesof the gear'teeths'othat there is no communicationbetween the small chambers defined by the chamfers and'the exteriorofthe gear teeth except atthe point of dead 'center'between the gears.'As indicated in FIGURES of the drawings, and as indicated indotted'o'utline in FIGURE3 of the'drawings, a narrow slot or passage 47is provided connecting the chzimfers43 'and 45 at 'one end of thegears'16 and 17 and conn'ectingthe chamfeis '44 and 46 at the oppositeend of these-gears. This passage 47 is substantially narrower'th'anthewid'th of'the gear teeth'and is betwee -bur not connected with theinlet and outlet 'passages 30 and 31. The purpose of this groove 47 ateach vend of the gears is toQpe'rinit' the escape of flu'idtrap'pedbetween the teeth astheteethpass through dead center positionbe'tweenthe 'ax'es ofthe 'gears. Thus "inplace of 'building'upa'highpressureinthe chamber 40 between the teeth of one gear and the base of the teethof the opposite gear, rhirpressure is permitted to escape through the.groove 47 for use in lubricating thebearings of thegears.

Asan actual example, in ahigh'pressure punip having a"p'urnp boreofperhaps fivefsixte'ehths of an inch, the

c'hamfer may "be abouffive 'to ten thousandths "of "an inch, and thegroove or passage connecting these cham- 'fe'rs'rnay be of about equal'width. 'At the hignpressu'res involved, this size is sufficient toproperly lubricate the journals.

In accordance with the patent statutes, I have described the principlesof construction and operation of my improvement in pump constructions;and 'while I have endeavored to set forth the best embodiment thereof, Idesire to have it understood that changes may be made within the scopeof the following claim without departing from the spirit of myinvention.

I claim:

A gear pump including,

a pair of intermeshing'gears,

parallel shafts supporting said gears,

a pump housingcompr'is'ing a'pair of sections ofsubstantially thesaniecrosssection throughout their axial lengths,

each "section including a 'pair of similar relatively shallowintersecting cylindrical cavities in a surface thereof,thecavities'mating to provide a gear chamber,

said sections including axial bores extending therethrough in concentricrelation tosaid cavities to accommodate saidshafts,

the juncture betweensaid boies and said cavities being chamfered, and inwhich each section includes a groove connectingsaid'chamfers at thepoint of tangency of said gears, .and

boltsarranged in angularly spaced relation about said cavities securingsaid sections together.

References Cited in the tile of this patent UNITED STATES PATENTS1,433,733 Lindsay Oct. 31, 1922 2,460,278 Cook Feb. 1,1949 2,624,287Ilyin June 6, 1953 2,642,808 Thomas .June23, 1953 2,816,511 Korkowski etal Dec. 17, 1957 FOREIGN PATENTS 353}8l1 Germany May 27, 1922 417,316Italy Jan. 14, 1947

